1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor integrated circuit device having, as basic elements, optical and electronic elements integrated to form an opto-electrical semiconductor integrated circuit used for optical fiber communication and the like.
2. Related Background Art
A structure obtained by integrating pin photodiodes (PIN-PDs) as light-receiving elements and field effect transistors (FETs) as electronic elements on a substrate is known as a reception front end in optical fiber communication.
Another conventional structure is also known in which PIN-PDs and FETs are monolithically formed on an InP substrate.
The structure having the light-receiving and electronic elements formed on a substrate is formed by soldering the respective elements on the substrate. Reliability of this structure is poorer than a monolithic structure, and the hybrid type structure is not suitable for mass production.
The conventional monolithic structure described above does not have bipolar transistors. A reception front end in optical fiber communication preferably has FETs having a high input impedance and low shot noise at its first signal amplification stage. In the subsequent stages, bipolar transistors having a large transconductance are preferably used. Therefore, strong demand has arisen for a monolithic semiconductor integrated circuit in which PIN-PDs, FETs, and bipolar transistors are formed on a single substrate, but such a semiconductor integrated circuit has not yet been developed.